There has been a constant progress in information infrastructure. People's lives have witnessed heavy infiltration of small- to middle-sized mobile liquid crystal equipment such as a mobile telephone, a PDA, a video camera, a digital camera, and an in-vehicle navigation. The majority of such mobile liquid crystal equipment includes a liquid crystal display device. In addition, the field of a large-sized flat-panel display has also witnessed highly active development and commercialization of a large-sized, large-screen liquid crystal television that is high in definition and excellent in resolution and that is thus high in contrast ratio. There has been a demand that such a liquid crystal display device should display a larger amount of information since equipment including such a liquid crystal display device mounted therein now handles a larger amount of information. The market has seen an increasing demand for achievement of an excellent display quality such as high contrast, wide viewing angle, high luminance, high color reproducibility, and high definition.
Much attention has been drawn to a liquid crystal display device including a liquid crystal layer of a vertical alignment (VA) display mode as a display mode that makes it possible to carry out a display that has high contrast and wide viewing angle. A liquid crystal display device of the vertical alignment (VA) display mode typically includes a vertical alignment film and a liquid crystal material having negative dielectric anisotropy. The VA display mode characteristically makes it possible to produce a high-contrast liquid crystal display device of a normally black (NB) display mode through a non-rubbing process.
(Conventional Art 1)
Patent Literature 1 cited below discloses a liquid crystal display device having a viewing angle characteristic that is improved by the arrangement of (i) generating an oblique electric field in the vicinity of an opening provided in a counter electrode that faces a pixel electrode across a liquid crystal layer and thus (ii) aligning, on the tilt, liquid crystal molecules present around vertically aligned liquid crystal molecules that are centrally located within the opening.
(Conventional Art 2)
Patent Literature 2 discloses, in order to remove, for example, an afterimage that is caused by an oblique electric field being non-uniformly generated in a display pixel and that is a problem posed in Patent Literature 1 and the like, a liquid crystal display device that includes a plurality of regularly arranged openings in a pixel electrode or in a counter electrode so as to have, inside a pixel, a plurality of liquid crystal domains each exhibiting an axial symmetry alignment.
(Conventional Art 3)
Patent Literature 3 discloses a vertical alignment liquid crystal display device (MVA liquid crystal display device) that includes, in a pixel electrode, (i) a plurality of slits (openings or notch sections) extending in parallel to one another or (ii) a plurality of projections (protruding sections) or depressions (hollow sections). This Patent Literature proposes a technique of providing alignment controlling means for regulating the direction in which liquid crystal molecules are tilted in response to voltage application, the alignment controlling means being provided in each of upper and lower substrates in a zigzag shape with respect to a pixel arrangement, that is, in two different directions in the respective upper and lower substrates. This technique thus achieves a four-domain alignment for a single pixel.
(Conventional Art 4)
Patent Literature 4 discloses a technique of regularly providing a plurality of protruding sections within a pixel to stabilize the alignment state in a liquid crystal domain, in which liquid crystal molecules are tilted and thus radially aligned around each protruding section as the center. This Patent Literature further discloses improving a display characteristic by, in addition to utilizing the above alignment controlling effect by the protruding sections, regulating the alignment of liquid crystal molecules with use of an oblique electric field due to an opening provided in an electrode.
(Conventional Art 5)
Patent Literature 5 discloses a technique related to a liquid crystal display device arranged such that, in order to stabilize the alignment state in a liquid crystal domain, (i) a color layer (colored layer) section of a color filter is removed from a portion including a slit structure provided in a counter electrode on the color filter and (ii) no planarizing film is provided for such a portion. This Patent Literature states that the use of the above structure can prevent the number of production steps from increasing due to the need to form a planarizing overcoat.
(Conventional Art 6)
Patent Literature 6 discloses a substrate technique for a liquid crystal display device including a color filter layer provided on a side of an active matrix (TFT) substrate on which side an array of active elements are provided. This Patent Literature proposes the above structure as a technique for improving display quality and reliability.
Citation List
Patent Literature 1
Japanese Patent Application Publication, Tokukaihei, No. 6-301036 A (Publication Date: Oct. 28, 1994)
Patent Literature 2
Japanese Patent Application Publication, Tokukai, No. 2000-47217 A (Publication Date: Feb. 18, 2000)
Patent Literature 3
Japanese Patent Application Publication, Tokukaihei, No. 11-242225 A (Publication Date: Sep. 7, 1999)
Patent Literature 4
Japanese Patent Application Publication, Tokukai, No. 2003-167253 A (Publication Date: Jun. 13, 2003)
Patent Literature 5
Japanese Patent Application Publication, Tokukai, No. 2002-174814 A (Publication Date: Jun. 21, 2002)
Patent Literature 6
Japanese Patent Application Publication, Tokukai, No. 2003-172946 A (Publication Date: Jun. 20, 2003)